Field of the Invention
The present invention relates to a method for forming a resist pattern.
Background Art
In lithography techniques, for example, a resist film composed of a resist material is formed on a substrate, and the resist film is subjected to selective exposure of radial rays such as light or electron beam through a mask having a predetermined pattern, followed by development, thereby forming a resist pattern having a predetermined shape on the resist film.
A resist material in which the exposed portions become soluble in a developing solution is called a positive-type, and a resist material in which the exposed portions become insoluble in a developing solution is called a negative-type.
In recent years, in the production of semiconductor elements and liquid crystal display elements, advances in lithography techniques have led to rapid progress in the field of pattern miniaturization.
Typically, these miniaturization techniques involve shortening the wavelength (increasing the energy) of the exposure light source. Conventionally, ultraviolet radiation typified by g-line and i-line radiation has been used, but nowadays KrF excimer lasers and ArF excimer lasers are starting to be introduced in mass production. Furthermore, research is also being conducted into lithography techniques that use an exposure light source having a wavelength shorter (energy higher) than these excimer lasers, such as electron beam, extreme ultraviolet radiation (EUV), and X ray.
As means for providing a further fine pattern, a double patterning process is suggested, in which patterning is performed a plurality of times to form a resist pattern. According to the double patterning process, for example, a first resist pattern is formed by performing patterning on a support using a first resist composition and then patterning is performed on the support on which the first resist pattern is formed using a second resist composition, so as to be able to form a resist pattern with higher resolution than that of the resist pattern formed by performing patterning once.
First, Japanese Unexamined Patent Application, Publication No. 2013-164509 discloses a method in which a first resist pattern is formed on a support, a SiO2 film is formed on the support where the first resist pattern is formed, etching is performed using the SiO2 film as a sacrifice film, and then the first resist pattern is removed to form a second pattern of the SiO2 film.